Numerous solutions were developed for providing safety faucets, such as described in the patents DE-32.18.091, EP-0.557.696, EP-0.653.581, GB-2.073.373, WO-99/31.417 or WO-99/39.119, however, in all of them, the operating arm can be turned only to the rotation direction, thus the faucets operate only in a given series so that at turning the arm, first the cold water starts to flow, and by turning it further, more and more hot water is mixed to it, until in the exterior position only hot water is flowing. The advantage of this solution is that the faucet can be opened only by opening the cold water.
As to their arrangement, these faucets are similar to the normal single-grip faucets, i.e. in the cartridge of the faucet a fixed inlet disc is situated underneath, and above it, a rotating regulation disc can be found which form together a plane seal. In the inlet disc, the inlet channel for the cold water connected to the water network and the inlet channel for the hot water are situated in an excentric position, whereas in its centre the outlet channel for the mixed water connected to the discharge outlet pipe end is to be found, whereas in the regulation disc, in the zone of the inlet channels two flow-through channels, and in an overlapping position with the outlet channel, a flow-back channel are developed. The common cross-section of the inlet channels and the flow-through channels determines any time the flow-through cross-sections, i.e. the amounts of the cold and hot water flowing through the system. The regulation disc is connected from above to an operating element. In the operating element, the mixing space is developed above the regulation disc, which is in a permanent connection with both the regulation channel and the flow-back channel. The operating arm of the valve battery is fixed to the upper part of the operating element either directly, or through a carrier element.
The difference between a normal faucet and a safe faucet consists in the form of the inlet channels and the regulation channels. As the regulation disc makes only a rotating motion, the arrangement of the inlet channels and the regulation channels should be so that their mutual turnings should regulate both the absolute and the relative amounts of the cold and hot water flowing through the system. It can be seen from the patents cited above that at choosing the forms and arrangement of the inlet and the regulation channels, different viewpoints could be considered, thus they show a very large variety.
Hospitals and laboratories generally required a much longer operating arm as usual, for the sake of easier handling. Based on this requirement, a construction trend was born, in which the outlet stump and the operating arm was unified. For this, several examples are shown in U.S. Pat. No. 4,768,557.
In one embodiment a rotating slide valve of horizontal axis is situated in the housing of the faucet, the outlet arm is fixed to its one end of this slide valve. In the rotating slide valve, in the vertical planes relative to its axis two oblong openings are situated shifted relative to each other, they turn above the inlet borings developed in the housing. The amount and the temperature of the water can be regulated by turning the slide valve, in the extreme position they are closed, thus from one closed position to the other, the whole regulation should be performed.
This version has also an embodiment having plane discs in which the slide valve of a horizontal axis is substituted by plane discs having also horizontal axes.
In an improved embodiment of the previous example, two slide valves are within each other, one is regulating the amount, the other one the temperature. The slide valve in inside is provided with a rotating knob opposite to the outflow arm.
In another version the regulating element is a slide valve can be shifted vertically and can be rotated around its axis. The outlet arm elevates and drops the slide valve by a gear-rack transmission, this provides the quantity regulation, and at the same time, it is in a carrying connection with the slide valve in the rotation direction, the rotation of the slide valve ensures the temperature regulation.
In one embodiment of the rotating and axially moving solution, the outlet arm divides the slide valve into two parts, and moves it axially by an excenter arrangement. This provides the temperature regulation. Tilting of the outlet arm rotates the slide valve, and this provides the regulation of the amounts.
In a third version, the regulating elements are traditional plane discs characteristic for single-grip faucets. The outlet arm is connected into a collar of hemisphere form sealed in the housing of the valve battery. The mixing space above the regulation disc is developed between the collar and the regulation disc, and not in the carrier element being in connection with the regulation disc.
Another basic operation principle is shown in U.S. Pat. No. 5,685,339. In this, a ball valve is situated in the housing of the faucet, with an upside-down Y-formed duct in it. The outlet arm is connected to the shaft of the Y, and opposite to the shafts, the inlet openings for the cold and hot water are developed in the housing. At turning the ball valve in the plane of the inlet openings, temperature regulation occurs, turning from this position to every direction, the inlet openings are closed.
In the above solutions, in addition to the possibility of shifting, another disadvantage is that their production is unfavourable due to their complicated structure.